Return trap



Jul v y E. I... CURTIS-STANFORD 1'636626 RETURN TRAP Filed Oct. 17. 1925 5 Shoots-Shut 2 IN YEN T0]? 602%! '5" Stanford Erz'a' L.

ATTORIVEK July 19, 1927.

E. L. CURTIS-STANFORD RETURN TRAP Filed Oct. 17. 1925 5 Shoots-Shoot 4 M A TTORNEVS E. L. CORT-lS-STANFORD RETURN TRAP Filed Oct. 17, v1 925 5 Shoots-Shut 5 INVENTOR Er"? 01602 2 L5 Stan/0rd Br 646m A TTOR/VEKS Patented July 19, 1927.

. 1,636,626 UNITED STATES PATENT OFFICE.

ERIC LORNE OORTIS-STANFORD, OF BIRMINGHAM, MICHIGAN, ASSIGNOR TO W. H. NICHOLSON 8:: COMPANY, OF WILKES-BARBIE, PENNSYLVANIA. A CORPORATION OF PENNSYLVANIA.

RETURN TRAE.

Application filed October 17, 1925. Serial No. 63,119.

My invention relates to a return trap, and particularly to a trap for collecting and returning condensate to a boiler, although my invention is applicable to any like system. Among the objects of my invention may be mentioned briefly (1) An automatically operating trap which collects liquid at low pressure and discharges at high pressure;

(2) An automatically operating trap which discharges by gravity at lriigh pressure;

A float-operated mechanism controlling the low and high pressure connections of the trap during collecting and discharging periods respectively;

i) A diflerential piston controlling a cut-off valve at the high pressure inlet to the trap;

(5) A counter associated with the trap mechanism to indicate its operations;

(6) Various features of novelty in construction and system hereafter described or shown in the accompanying drawings, in which Fig. l is a perspective view illustrating the application of my invention to a layout in which the trap and an associated collect-' ing tank are arranged above the boiler;

Fig. 2 is a side elevation of a modified arrangement in which the collecting tank and trap are arranged below the water level of the boiler. and a second trap above the latter for discharging to the boiler;

Fig. 3 is a broken side elevation through the trap illustrating the position of the parts when the trap has discharged;

Fig. i is a broken side elevation of the trap head and the exhaust valve for the differential piston;

Fig. is a broken side elevation of the trap showing the position of the parts when the trap is about to discharge;

F 6 is a broken end elevation of the trap;

Figs. 7 and S are partial sections on lines 7-7 and 88 respectively, Fig. 6;

Figs. 9 and 10 are side elevations of the trap head showing the float and trip mechanisms in different positions.

A returntrap of the present type is particularly useful and is therefore shown in a heating system in which steam is carried at low pressure through heating pipes and radiators, say at a pressure of 5 pounds, (or

Referring to Fig. 1, which illustrates a typical layout, the return piping leads condensate from the radiators to a collecting tank 16. From the latter the water passes by intake pipe 17 to the trap 18 and is discharged thence by outlet pipe 19 to the lower portion of the boiler 20. The pipe 17 is connected to the trap through a T-litting 21 in advance of which is arranged a check valve 22. The outlet pipe 19 is connected to the opposite branch of the T-fitting 21 through intermediate check valve 23, which is normally closed by pressure from the boiler 20.

From the T-fitting 21 the water enters the trap 18 through port 24 and gradually fills the chamber While the latter is at low pressure. Then the trap is filled to predetel-mined level, steam from the boiler 20 is admitted to the trap and places the chamber under boiler pressure. This results at once in closing the check valve 22 in feed line 17 from collecting tank '16. Inasmuch as the trap is now under a pressure corresponding to that in the boiler 20, the pressure upon opposite faces of check valve 23 in dis charge line 19 is now balanced. The hydraulic head of the water in the trap now suffices to open the check valve 23, so that the water flows by gravity through outlet line 19 into the boiler. lVhen the trap has sutliciently emptied, the mechanism again exhausts the trap chamber of its pressure, whereupon the check valve 23 is again auto matically closed by pressure from the boiler, while check valve 22 now relieved from pressure, again opens to admit the condensate from the tank 16. The cycle repeats auto matically.

The mechanism controlling the pressure in the trap chamber is operated by the float 26 and the associated weight lever 27, the latter fast with the axis 28 upon which the float is loosely journalled. A crank .valve operating cam or crank 29 is fast with the y v V I 1,636,626

axis 28 and moves With the rise-and fall of the Weight lever 27. The latter extends across the axis'28 and has a head 30 slotted at 31 to receive a-pin 32. carried by thefloat leverza-nd affording a lost motion connection therewith. A pivoted catch .33 en ages a notch 34 in the head 30 of the Weight arm and holds the latter in raised position, While the float ascends; When the float has risen to a predetermined extent, its pin 35 bears against the arm 36 of the catch and swings the'latter tree of-the'notclr 34, thus releasing constantly atboilerpressure through pipe 4? from the boller 20; which preferably leads to thereceiving tank the'Weigl1t-27 and permitting the latter to drop,- and thus swing the crank 29 t0 -va-lve opening position. 1 j I As the =fl'oat26 drops, it engages a fork '37, at the itee end of the lever 38, fastwith pivot-pin 39[ The latter passes through-the An exhaust pipe i8,

16, although it n'iay discharge to atn'iosphere if preferred, terminates a-t-port 49 2l(l]fl0011t port 45. Ports and 49 by Which they may be put in communication.

- In unsposition 'of the valve, the trapchainher is' in: communication with collecting chamber l6 (or atmosphere) through pipe i l, port'4l5, valve 50, port i9,'and pipe 48.

The slide valve 50 is mounted upon rod 51 oia dili'ercntial piston, the-head 52 of which is otfgreater diameter than the head 5;). vVhen the pressure against the outer faces of the pistons is substantially equal,

. theboiler pressure in the steam'chest 46. to

Whiehthe adjacent ends of thepiston eylin- I ders open,,shi:fts the pistons to the position 7 trolled" by indicates in Fig. 6 b reasonv of the greater V rm area ofthe'piston 52. 7

Communicating with theouter end of the cylinder for" piston .52, is a passage 54 convalve 55 and opening through pipe 5am the'qexhaust line 48." Also op'ening'to this endofthecylinder is a second passage- 57*(Figi- 3) which connects through pipe 58 and valve 59 with pipe 60, which opens, through passage 61, to the'steam chest; Ob

'viously if the pressure against the inner faceot the large piston 52 be' balanced against "itsout-er face, bythe' admission of I steam from thechesttlirough'passages 57 58;

valve 59' and passagesGO, 61, the equalized pressureson. opposite' faces of this piston,

coupled the still unbalanced thrust (Fig.- '6) are. spanned by aslide valve 50 oi. the U- typ-e, I

against piston '53, results-in the displacement of the piston 53 to its opposite extreme position (Fig. 5). This movement shifts the slide v"lve 50 to uncover; port 45 (While naint I41 ingportdfi) closed), andlsteamfroin the chest 46 passes through pipe 4 lto the interior oi the trap (Fig. 5).

The boiler pressure thus admitted to the trap,rresults at once in closing the check valve 22 in the feed line 17. Inasmuch as pressure is new balanced onv opposite sides of the check valve 23 in discharge line 19, the hydrostatic head ofthe Water in the trap opens the check valve 23 and the water flows freely by gravity from theltrap to the boiler.

lVhen the-trap has snlficiently discharged, valve 55 is opened, and the pressure against the outer faceot piston 52 is relieved by the escape of the steam throughpassages 54.: and--56 to the eXhaust-lin'el8. At one-e the differential. piston returns to its original 130- sition, thus shifting the slide valve 50 to'the position in which it spans the ports 45, 49. Steam under pressure in the trap noW'exhausts through the pipe 44: and ports 45, 49 to the exhaust line 48, check valve 23 aut0- matical'ly shuts under pressure from the boiler, while check valve 22 opens to admitcondensate again to the trap from the tank' 16; The cycle automatically repeats.

It 'Willbe-ohserved that when the trap drained (Fig. the" falling float 26 lifts the Weight-27- and'thus' swings the crank 29 downward. This pern'iitsvalve 59' to close, cutting oil 'Pl'GSSLU'G to the outer end ofpisten 52. I As the float falls further the floatoperated lever 38 is depressed and kicks open valve 55in line-54t56 through which the steam escapes from the outer end of the piston to the exhaust line48. The differentialpiston then shifts automatically and returns'the U-valve 50 to the position in which it s; ans the ports-45, 4-9, so that'the trap exhausts its steam pressure, and reStoresconditions forre-entry of Water from tank 16. hen the float rises-again it? kicks off the trip a d the falling Weight 27 rotates the crank 29 to open the valve 59 again, and the cycle of operationsrepeat-s.

A; counter mechanism 64 may be associated withthelever4l through the link '65 and lever 66, by Which a record of the number of trap operationsmay be automatieally'kepti Since there may be some leakage past the piston 53, a drip cup 67 may be mounted beneath'the lower end-of the cylinder 62 and connected by pipe 68-Withtheexhaust line48- Under certain conditions it is necessary to arrange theeolleot ng or sump: tank 16 at the floor level oftlieboil'er, in which case some s stems" sufiicient ressure exists-in the tank 16 to raise the water to the trap level, particularly if the exhaust from the float chamber of the trap be directly to atmosphere instead of to the tank 16. In other systems this is not feasible, and for such layouts, of which Fig. 2 may be regarded as typical, I supplement the trap 18 at the boiler head by a second trap 180 at the floor level. The tank 16 feeds the trap 180 through line past check valve 71. The trap discharges past check valve 72 to riser 7S, thence to trap 18 past check 74, and discharges from the trap past check 75 to downcomer 76 connected to the boiler. The steam chests 7778 of both trap valve mechanisms are connected to the boiler through lines Bil-81. The exhausts from the float chambers and differential piston cylinder ends of both traps connect through branches 82-83 with the return line 84 leading to the tank 16 past check 85. The tank receives condensate from the heating system through line 86 past check 87.

In a layout such as this, the trap 1.80 acts as a pump, since the pressure from riser 73 on check 7 does not equal that exerted upon the water in the float chamber by the steam when the latter is admitted by the valve mechanism (Figs. 3-10) above explained. Consequently the water in the trap 180 is driven up to trap 18 past checks 724 i, and thereafter discharges by gravity to the boiler through return 83 in the same manner as in the layout of Fig. 1.

Various details of the mechanism present advantages. Thus (1) the pressure chest and differential piston cylinders are cast in one with. and all the moving parts are carried on. the head 63 which forms an end closure of the float chamber casting 18. It is thus possible to mount all. oil the parts upon this head at a convenient work bench before a. scinbly on casting 18. All of the valves are held to their seats by steam pressure, and are positively opened against the latter. (3) The lost motion connection between the weight end 30 and float lever insures a quick snap y opening of the valve 59. The adin' .sion of steam to the float chamber oc curs above the water level, Consequently no disturbance of the water occurs when the pre sure connection is established. (5) The exhaust follows the same line to the slide valve-and is in no danger of imped- .1 (6) The water inlet and outlet pas sages are of the simplest possible sort -as as the check valves which control them. latter are to a large extent self-clearing,

there is little or no danger of failure to seat properly or of becoming choked. (i) The exhaust pipe d8 has a lJ-bend in which condensate from the exhaust steam collects and is periodically blown into the tank 16 by the steam exhausted from the float chamber and cylinder head. (8) To install the trap requires only connections from the T-litting 21 to tank 16 and boiler 20; and from steam chest 41:6 to the stean'i dome of the boiler; and preferably, hough not necessarily, fro-m the exhaust 48 to the tanl: 1G. The trap is otherwise self-contained.

l t will be realized that the collecting tanlr or sump 16 is merely a convenience which may be dispensed with, since the drainage lines 15 of the system may be connected directly with the trap feed line 1 while the float chamber exhaust 48 may discharge to atmosphere. Various other modifications of the system, as well as changes in detail cit construction and arrangement of parts, which embody what I claim as my invention, will readily occur to those dealing with the problem.

lVith the understanding therefore that the draw'in s illustrate, and the foregoing description explains only specific embodiments of the thoughts which underlie my invention, I claim:

1. A return trap comprising a float cham her, a pivoted float therein, a pivoted weight lever, afloat-operated trip for releasing the weight lever on the rise of the float, a piss ton-operated slide valve controlling the admission of pressure to the float chamber, a valve controlling the admission of pressure to the piston cylinder, and an operating connection between the weight lever and piston cylinder admission valve for opening the latter on the fall of the weight lever.

2. A return trap comprising a float (.lltllllher, a pivoted float therein, a pivoted weight. lever, a float-operated trip for releasing the weight lever on the rise of the float, a pis ton-operated slide valve controlling the ailbetween said lever and the tloat for actuat ing the lever upon the fall of the float.

3. A return trap comprising a trap body and a closure head therefor, a pressure chest. on. the outer face of said head with differ ential piston cylinders at opposite ends r: said ches means for establishing constant communication between said chest and a source of pressure, ports opening from said chest respectively to the interior of the trap body and to an exhaust line, a slide valve controlling said ports, differential pistons arranged in said cylinders and ope atingsaid slide valve, a passage opening from steam chest to the outer face of one of pistons, a valve mounted on the inner lace rsaid closure head and controlling said i age, in combination with a. float pivotalrpm-red on the inner face of said head, a pivoted weight lever also supported at the inner face of id head, a float-operated trip device supporting said weight-lever in raised sition but float operated to release said git lever on the rise of the float, and

an o )eratingconnection between said wei ht lever and said valve in the control passage t it the other piston and thus shifts the slide valve to uncover the port-leading from ti o chest to the interior of the float chamber. 7

4. A return trap comprising a trap body and a closure head therefor, a pressure chest on the outer face of said head with differential piston cylinders opposite ends of said chest, means for establishing con stant communication between said chest and a source of pressure, ports opening from said chest respectively to the interior of the trap body and to an exhaust line,,a slide valve controlling said ports, differential pistons arrangedin said cylinders and operating said slide valve, a passage opening from said steam chest to the outer face. of one of said pistons, a valve mounted on the inner face of said closure head and controlling said passage, in combination with afloat pivotally supported on the inner face of said head, a pivoted weight lever also supported at the inner face ofsaid head, a float-operated tripfdevice supporting said weight lever in raised position butfloatoperatcd to release said weight lever on the rise of thc float, and an operating connection between saidweight lever and said valve in the control passage to open said valve on the fall of the weight lever'to establish equalizing pressure on opposite faces of one of said difl'erential pistons whereby the latter is dis placed by the unbalanced pressure against the other piston and thus shifts the slide valve to uncover the port leading from the chest tothe interior of the float chamber, together with a relief passage opening to the equalizing chamber of said piston cylinder, a valve controlling said relief passage, a lever for opening said relief valve, and means actuated by the fall of the to open said valve, whereby the di'flierential pistons arereturned to normal. position and theinterior of the trap is placed in c inunication through said slide valve with the exhaust passage.

In a return trap, a float chamber body,

a: closure head therefor, a piston-operated slide valve arranged in the outer face ofwsaid,

outer face of said closure head to control closure head, a relief valve arranged in theuj the exhaust from the slide valve operating piston, in combination with a float arranged for actuation by the float on the fall'of the latter. I

6. In a return trap, a float chamber body, a closure head therefor, a piston-operated slide valve arranged in the outer face of said closure head, a relief valve arranged in the outer face of said closure headtocontrol the exhaust fromithe slide valve operating piston, in combination with a floatar ranged within the trap chamber, and pivotally mounted at the inner face of said closure head, a lever pivoted in said closure head and having an associated element extending to the outer face of said closure headto operate said relief valve, the portion ofvsaid lever extending within the trap chamber being operatively associated with the float for actuation by the float on the fall of the latter, together with a counter mechanism arranged at the outer face of said closure head and actuated by said lever element.

"1'. A return trap having apiston-operated slide valve controlling admission of, pres sure to and from the trap chamber, a pressure cont ol chamber associated with the slide valve operating piston, a float lever within the chamber, a weight lever lifted by the fall of the float, a trip device for taining the Weight lever, means associated to fall, together with a valveopened by the i fall of the weight leverto'. admit pressure to the piston control chamber. o q I i o. A return trap having a piston-operated slide valve controlling admission of pressure to and from the trap 'chan'iber, a pressure control chamber associated w1th the slide valve operating piston, a float lever Within the chamber, a weight lever lifted by the fall of the float, a trip devicefor sustaining the weight lever, means associated with the float for releasing said trip on the rise of the float to permit the weight lever to fall, together with a valve opene'd-bythe fall of the'wcight lever to admit pressure to the piston control chamber-fin combination with a relief valve associated with said control chamber, and an operating lever therefor actuated bythe fall of'the float. I g

In testimony whereof Ihave signed'my name to this specification.

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